Stacked Filter Unit Sampler Research Articles

Helium and Proton Particle-Induced X-Ray Emission (PIXE) for Characterization of PM2.5 from Surabaya, Indonesia

Generally, particle-induced X-ray emission (PIXE) analysis is performed using protons as the incident projectiles. In this study, helium ions were used for inducing X-ray emission to improve the detection limit for the characterization of light elements in the PM2.5 fine fraction. The sampling was conducted for 24 h using a Gent stacked filter unit sampler at an industrial site in Surabaya, Indonesia. The samples were analyzed by PIXE using a 4-MV Van de Graaff accelerator at Kyoto University. Both helium and protons were used in the analysis to obtain optimal results, and 21 elements were detected in the samples. Notably, the use of helium particle-induced X-ray emission was more suitable for Na, Mg, Al, and Si than protons. Moreover, the sensitivity and limit of detection for these elements were enhanced using helium ions. Validation was performed using standard reference material NIST 2783 air particulates on filter media, and the results were in good agreement. Using both He-PIXE and H-PIXE, heavy metals, crustal elements, and other elements were identified that exhibited the characteristics of PM2.5 collected in Surabaya, Indonesia. Further statistical analysis and receptor modeling are required to identify the possible pollutant sources of PM2.5.

Assessment of Urban Air Quality in Indonesia

ABSTRACT This study assessed the urban air quality in 16 large Indonesian cities on the islands of Java, Sumatra, Kalimantan, Sulawesi, Maluku, and Papua from 2010 till 2017. 24-h samples of airborne particulate matter (PM) in two size fractions, PM2.5 (< 2.5 µm in aerodynamic diameter) and PM2.5-10 (2.5–10 µm in aerodynamic diameter), were collected weekly using a Gent stacked filter unit sampler and then analyzed for their mass concentrations, black carbon (BC) content, and elemental compositions. The majority of the average annual PM2.5 concentrations measured at the Java sites (Bandung, Jakarta, Semarang, and Surabaya) exceeded the Indonesian annual ambient air quality standard (15 µg m–3), although the other tested locations, excluding Pekanbaru and Palangka Raya, exhibited values below the standard. During the forest fire episodes of 2015, the average daily PM2.5 concentrations in Pekanbaru and Palangka Raya rose above the national daily ambient standard (65 µg m–3). The percentage of BC, which is associated with traffic emission and biomass burning, averaged between 15% and 26% (a significant fraction) in the PM2.5. The concentrations of the major elements in the PM2.5, viz., Si, S, K, Fe, Zn, and Pb, varied widely from site to site, although all of the locations displayed enhanced levels of the crustal elements Si and S, which originated from unpaved roads and volcanic eruptions, and vehicle fuel, forest fires, and volcanic emissions, respectively. Significantly higher concentrations of heavy metals (Fe, Zn, and Pb in Surabaya and Pb in Tangerang) were found at the heavily industrialized sites, demonstrating the effect of local industrial emissions on air quality. Our results, which are based on a crucial survey of PM concentrations and compositions in Indonesia, provide a scientific basis for developing and improving various air quality policies in the nation, including an early warning system for severe pollution events.

Chemical Composition of Fine Particulate Matter from Peat Forest Fires at Palangka Raya and Its Dispersion using HYSPLIT

An air quality monitoring was conducted to investigate the chemical characteristics of particulate emissions in peat forest fires at Palangka Raya, Indonesia during 2012 where a peat forest fire episode occurred. Aerosol samples were collected at Palangka Raya where represents a sub urban site downwind of the peat forest fires. The samples were collected using Gent stacked filter unit sampler. The sampler provides two size fractions: coarse (2.5-10 μm equivalent aerodynamic diameters EAD) and fine (<2.5 μm EAD). Black carbon (BC) was measured using Smoke Stain Reflectometer, and elemental compositions were analyzed using X-ray Fluorescence (XRF). The concentrations of PM2.5 during a haze episode were significantly different about seven to eight times higher when compared to the concentrations in non-haze conditions. The major components of PM2.5 in peat smoke haze consist of sulphur, biomass burning component (BC, K), and crustal components (Al, Fe, Si). The sulphur mainly comes from the peat as it is the earliest stage of transition from compressed plant growth to the formation of coal. The dispersion pattern to show the effect of wind direction using the Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) simulation was also applied.

Respiratory symptoms, lung function and particulate matter pollution in residential indoor environment in Ile-Ife, Nigeria.

Introduction:Particulate air pollution is associated with increased incidence of respiratory symptoms and decreased pulmonary, function but the relative impact of pollution from different domestic energy sources is not well-known or studied.Aim:The study was aimed at assessing the association between particulate concentrations, respiratory symptoms and lung function.Materials and Methods:It was a cross-sectional study comprised of randomly selected residents of three communities. These communities were selected according to the predominant type of fuel used for household cooking which were: firewood, kerosene and liquefied petroleum gas (LPG). Assessment of the indoor PM10 levels was done by filtration using the Gent stacked filter unit sampler for collection of atmospheric aerosol in two size fractions (PM2.5 and PM10). The Medical Research Council (MRC) questionnaire was administered followed by spirometry test.Results:The mean PM10 concentration in participants using LPG, kerosene and firewood was 80.8 ± 9.52 μg/m3, 236.9 ± 26.5 μg/m3 and 269 ±93.7 μg/m3, respectively. The mean age and height-adjusted percent predicted forced expiratory volumes in 1 s (FEV1) for men were 127 ± 7, 109 ± 40 and 91 ± 20 and for women were 129 ± 13, 115 ± 14, 100 ± 14 in users of LPG, kerosene and firewood, respectively. A similar trend was found in the forced vital capacity (FVCs). Users of firewood had significantly lower FEV1 and FVC compared with LPG users (P < 0.05). The participants using firewood had the highest prevalence of pulmonary and non-pulmonary symptoms (57.1%), whereas subjects using LPG had the lowest (23.8%).Conclusion:There are high levels of particulate matter pollutions with respiratory effects in residential indoor environments in Ile-Ife, Nigeria

Long term airborne lead pollution monitoring in Bandung, Indonesia

Lead poisoning is one of the environmental problems affecting human health. In Indonesia, leaded gasoline was completely phased out since July 2006. As part of an air pollution study, Pb monitoring was carried out from 2005 to 2012 in Bandung to assess the impact of the use of unleaded gasoline on the Pb level in the ambient air in Indonesia. Airborne particulate samples were collected using a Gent stacked filter unit sampler in two size fractions of [Formula: see text] (fine) and 2.5 to [Formula: see text] (coarse). Black carbon (BC) was determined by reflectance and elemental analysis was performed using particle induced X-ray emission (PIXE). The results showed that the annual averages of lead concentrations in the fine particulate matter in 2005, 2006, 2007, 2008, 2009, 2010, 2011 and 2012 were 44.53, 27.06, 22.21, 17.75, 17.21, 16.24, 19.25 and 12.69 [Formula: see text], respectively. The airborne lead concentrations showed a declining trend over the years after implementation of the government policy of phasing out leaded gasoline. After six years of monitoring, the lead concentration in PM2.5 was decreased by over 70% compared to samples collected before July 2006. The average of PM mass, BC and elemental concentrations are also presented and discussed. The significant decrease of Pb concentration in the ambient air of Bandung is a great success story of the phase out of leaded gasoline in Indonesia.

CHARACTERISTIC OF AIRBORNE PARTICULATE MATTER SAMPLES COLLECTED FROM TWO SEMI INDUSTRIAL SITES IN BANDUNG, INDONESIA

Air particulate matter concentrations, black carbon as well as elemental concentrations in two semi industrial sites were investigated as a preliminary study for evaluation of air quality in these areas. Sampling of airborne particulate matter was conducted in July 2009 using a Gent stacked filter unit sampler and a total of 18 pairs of samples were collected. Black carbon was determined by reflectance measurement and elemental analysis was performed using particle induced X-ray emission (PIXE). Elements Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn and As were detected. Twenty four hour PM2.5 concentration at semi industrial sites Kiaracondong and Holis ranged from 4.0 to 22.2 µg m-3, while the PM10 concentration ranged from 24.5 to 77.1 µg m-3. High concentration of crustal elements, sulphur and zinc were identified in fine and coarse fractions for both sites. The fine fraction data from both sites were analyzed using a multivariate principal component analysis and for Kiaracondong site, identified factors are attributed to sea-salt with soil dust, vehicular emissions and biomass burning, non ferrous smelter, and iron/steel work industry, while for Holis site identified factors are attributed to soil dust, industrial emissions, vehicular emissions with biomass burning, and sea-salt. Although particulate samples were collected from semi industrial sites, vehicular emissions constituted with S, Zn and BC were identified in both sites.

Elemental characterization of urban particulates at receptor locations in Abuja, north-central Nigeria

The rising population and increasing urban infrastructures of Abuja have led to increased pressure on the urban environment. Two decades after putting the city of Abuja to use, there is yet no information on the air quality status of the city. Hence, this study was conducted in order to assess the mass concentration and elemental characterization of airborne particulate matter in Abuja, north-central Nigeria. Sampling of PM2.5: aerodynamic diameter ≤2.5 μm and PM10: aerodynamic diameter ≤10 μm were carried out in five urban sites within the city from April, 2009 to May, 2010. "Gent" stacked filter unit sampler equipped with a double stage filters in series was employed for sample collection. Charged helium (4He+) Particle Induced X-ray Emission technique of 2500 keV particle energy and Genie 2000 software were used for spectra acquisition while elemental characterization was achieved using Gupixwin software in order to determine the concentration of eighteen elements (Si, S, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Sn, Ba, Ta and Pb). Mass concentrations range between 7–86 μg m−3 and 22–343 μg m−3 for PM2.5 and PM10 respectively. Crustal elements (Si, Ca, and Fe) were found to be predominant in PM10 than in PM2.5 fraction with very high values. Positive correlation r > 0.90 and r > 0.53 to 0.90 exist between metals (V, Co, Ni, Cd, Zn and Pb). PM2.5/PM10 mass ratios were well within the range specified by WHO for developing urban scenario.

Ten-year study of fine aerosol at Sde Boker, Israel, using PIXE: Time trends, seasonal variation, correlations, and source areas for anthropogenic elements

From January 1995 through December 2004 aerosol samples were collected at Sde Boker, Israel, with a Gent stacked filter unit sampler. The collections were done according to a 2–2–3day schedule, which resulted in about 150 samples per year. The samples were analysed for the particulate mass (PM) by weighing, for black carbon (BC) by a light reflectance technique, and for up to 46 elements by a combination of PIXE and instrumental neutron activation analysis. Here, we report on the fine (PM2) size fraction data for the PM, BC, and the following nine anthropogenic elements S, V, Ni, Cu, Zn, As, Se, Sb, and Pb, and discuss their time trends, seasonal variation, correlations, and source areas. The largest changes in the annual medians over the 10-year period were found for S, Ni, Se, Sb, and Pb, i.e., of −34%, −25%, −47%, +26%, and −40%, respectively. The seasonal variation was largest for S, with 1.6times higher concentrations in summer than in the other three seasons. Vanadium and Ni were very highly correlated with each other (r=0.95), pointing to a dominant common source, which is undoubtedly oil burning. Trajectory statistics, using 10-day back trajectories with arrival at 300m above ground, were applied to assess the source areas. Sulphur originated mostly from south-eastern Europe (i.e., Turkey, Bulgaria, Romania, Ukraine, and southern Russia) and As from the south-eastern part of European Russia, whilst the source picture for Zn was rather unclear. The other six anthropogenic elements and BC seemed to originate mainly from regional sources.

Atmospheric black carbon in PM2.5 in Indonesian cities

Samples of airborne particulate matter were collected at several cities in Indonesia: Bandung, Jakarta, Palangka Raya, Serpong, and Yogyakarta, from January through December 2011. The samples were collected once a week using a Gent stacked filter unit sampler in two size fractions of 2.5 µm (fine, PM2.5) and 2.5 to 10 µm (coarse, PM2.5–10). Black carbon was measured using an EEL smoke stain reflectometer. The average of PM2.5 during the sampling period for Bandung, Jakarta, Palangka Raya, Serpong, and Yogyakarta sites was 18.35, 16.50, 7.74, 16.68, and 8.78 µg/m3, respectively. The average of BC for Bandung, Jakarta, Palangka Raya, Serpong and Yogyakarta was 3.05, 3.37, 3.19, 2.51, and 2.20 μg/m3, respectively. The ratio of the 24-hr BC concentration compared to the PM2.5 concentrations showed that BC comprises about 17–45% of the fine particulate matter collected at all sites. The average percentage of BC in PM2.5 concentrations in Bandung, Jakarta, Palangka Raya, Serpong, and Yogyakarta was 18, 22, 45, 17, and 26%, respectively. Bandung and Jakarta compared with Yogyakarta showed higher concentrations of PM2.5 and BC, which indicated pollution occurring in Bandung and Jakarta is more intense than in Yogyakarta, while the maximum of BC concentration and the percentage of BC in PM2.5 in Palangka Raya were 6.04 μg/m3 and 75%, respectively. This higher BC concentration than the other cities was due to the forest fires that occurred frequently during the sampling period. The contributions of BC source in these cities were also analyzed to ascertain the local sources of BC. Implications: BC in PM2.5 was monitored over the period of January–December 2011 in several big cities in Indonesia to provide quantitative information on BC concentrations and contributions to PM2.5 and for comparison among these cities and with other Asian countries. This study supports the national air quality monitoring projects. The results of black carbon concentrations in these areas indicate source contributions from local sources such as forest fire, biomass burning, and vehicle emissions.

Atmospheric particulate matter in Nigerian megacities

The paucity of data on air pollution indices in Nigeria prompted us to commence a national screening exercise regarding particulate matter loads. Six potential megacities (Aba, Abuja, Lagos, Kano, Maiduguri, and Port-Harcourt) representing the six geographical zones in Nigeria were chosen for the study. Sampling was achieved using a ‘Gent’ stacked filter unit sampler capable of collecting fractions of particulate matter with sizes of <10-μm and <2.5-μm simultaneously. The mean values for PM10 are 550, 35, 87, 340, 246 and 130 μg m−3 while for PM2.5 the mean values are 100, 14, 25, 67, 20 and 30 μg m−3 respectively for Aba, Abuja, Lagos, Kano, Maiduguri, and Port-Harcourt. Except for Abuja, the daily PM10 mass loads exceeded the World Health Organization (WHO) guidelines daily limit where as the PM2.5 values were within the WHO guideline limit. Their correlation matrix result indicates that some PM2.5 fractions mass fractions were strongly correlated than the PM10 fractions probably due to their long range transport potentials. Further work is in progress to determine the elemental profiles of both particulate fractions collected.

Characterization of airborne particulate matter collected at Jakarta roadside of an arterial road

A total of 44 pairs of airborne particulate matter samples were collected in the intersection of Simprug, Pondok Indah, South Jakarta. Sampling of airborne particulate matter was conducted in July 2008–July 2009 using a Gent stacked filter unit sampler in two size fractions of <2.5 µm (fine) and 2.5–10 µm (coarse). Mass concentrations, black carbon as well as elemental concentrations were investigated as a pre-study in step to the evaluation of air quality in these roadside areas. Black carbon was determined by reflectance and elemental analysis was performed using proton induced X-ray emission, PIXE. The data set of fine particulate matters obtained from the characterization was then analyzed using receptor modeling EPA PMF3 for source apportionment. Source apportionment identified 5 factors, i.e. soil (9.2 %), construction mixed with road dust (20.9 %), motor vehicles (31.5 %), biomass burning mixed with seasalt (30.9 %), and industry (7.5 %). Motor vehicles is the dominant sources that contributes to the fine particulate matter in Jakarta.

Determination of chemical elements in airborne particulate matter collected at Lembang, Indonesia by particle induced X-ray emission

Monitoring the air quality in ambient air is an important step for assessing the air pollution level in one region and its impact to the human health. In this study, the determination of chemical elements concentrations in airborne particulate matter collected in suburban area of Lembang, Indonesia was carried out. Samples were collected using a Gent stacked filter unit sampler in two size fractions of <2.5 μm (fine) and 2.5–10 μm (coarse). Sampling was conducted twice a week for 24 h from January 2008 to June 2009 and 123 pairs of samples were collected. Black carbon was determined by reflectance and chemical elements analysis were performed using particle induced X-ray emission (PIXE). PIXE as one of ion beam analysis techniques is suitable for analyzing particulate matter for its multielemental analysis with good limits of detection. Results showed that none of daily concentrations of PM2.5 and PM10 exceeded the 24 h Indonesian NAAQS for PM2.5 and PM10. Chemical elements such as Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Hg and Pb were determined and the correlation between these elements was reported in order to understand the anthropogenic sources of particulate matter.

Preliminary study on air pollution source identification in Xinzhen, Beijing, using NAA and PIXE

A total of 178 aerosol samples in two size fractions, PM10-2.5 (coarse) and PM2.5 (fine), were collected on nucleopore films using a Gent stacked filter unit sampler at the Graduate School of China Nuclear Industrial Group during May 2007 to November of 2009. Black carbon was determined by a reflectometer. A total of 16 elements, Mg, Al, S, Si, P, Cl, Ca, K, Ti, Mn, Fe, Ni, Cu, Zn, As and Pb, were determined by Particle Induced X-ray Emission. Mg, Al, Ca, K and Mn were also determined by Neutron Activation Analysis. Concentrations of all these elements were used to identify possible pollution sources and directions of the airborne particulate matter by means of softwares PMF and CPF. Some extraordinary events, such as sandstorms, firework and transboundary fire smoke were pinpointed by a combination of time series of multielement, relevant meteorological data and softwares Wind rose, Hysplit, and Google earth.

Preliminary study of the sources of ambient air pollution in Serpong, Indonesia

There has been increasing interest regarding air pollution in the Serpong area of Indonesia, a region near Jakarta, especially with respect to high concentrations of Pb detected in early 2001. Several studies have been conducted, but the appropriate action needed to control this pollution has not been identified because of inadequate identification of the particulate matter sources. In this study, source investigation was performed using the chemical characteristics of ambient airborne particulate matter samples from several locations in Serpong and its surroundings. Sampling of airborne particulate matter was conducted using a Gent stacked filter unit sampler in Serpong between August and November 2008. Black carbon (BC) was determined by reflectance and elemental analysis were performed using particle induced X–ray emission (PIXE). Al, As, Ba, Br, Ca, Cl, Co, Cr, Cu, Fe, Hg, I, K, Mg, Mn, Na, Ni, P, Pb, S, Sc, Si, Se, Sr, Ti, V and Zn were determined. The results showed that the higher Pb concentrations in both fine and coarse particulate matter were observed in the industrial area compared to adjacent residential areas. The Pb percentages in the collected PM2.5 mass in the residential and industrial areas were 3.1% and 4.3%, respectively, while for PM2.5–10, Pb represented 1.9% and 6.0% of the PM mass, respectively. The fine fraction data from two residential areas (Setu and EMC) were analyzed using EPA PMF (version 3) for source apportionment. The source apportionment identified 5 factors, i.e., lead industry and road dust (12%), diesel vehicles (30%), oil and power plant (26%), road dust (17%) and biomass burning mixed with road dust (15%).

Elemental Composition of Atmospheric Particulate Matter during 2006 Wet Season at a Rural Background Site in Tanzania

The elemental composition of PM10 was studied during 2006 wet season in a rural background site of Morogoro, Tanzania. A Gent PM10 stacked filter unit sampler with coarse and fine Nuclepore polycarbonate filters, providing fine (0.4 μm) and coarse (8 μm) size fractions, was deployed. A total of 29 collections were analysed for the PM mass by weighing. A further analysis was performed for 25 elements by particle-induced x-ray emission spectrometry. The results show that the concentrations of the heavy metals were lower than those for the elements of crustal origin. The data from PIXE analysis and enrichment factor (E.F.) calculation, using Fe as a reference of crustal material, showed that for the coarse size fraction, most elements have crustal EFs that are very close to one, while enriched elements (E.F. > 10) like S, Cl, Zn, As, Br, Pb and BC, predominated in fine (PM2) size fraction (an anthropogenic origin can be suggested for the later). Potassium a well-known indicator for biomass burning was mostly associated with the fine particles (as around 56% of the PM10 K was in the PM2 size fraction). This suggests that biomass burning was important in Morogoro. Five-day isentropic backward trajectories as determined by the air trajectory HYSPLIT model were computed for Morogoro and the allocated sector of oceanic origin over continental, mainly through Mozambique and Tanzania) was the most common. However, other sectors such as Oceanic, over Madagascar or continental origins were observed. @JASEM J. Appl. Sci. Environ. Manage. December, 2010, Vol. 14 (4) 135 – 139

An Investigation on Heavy Metals in an Industrial Area in Greece

In the industrial area of Elefsis, Greece, aerosol samples from the atmosphere were collected using a stacked filter unit sampler, which separates the airborne particulate matter into coarse (PM 2.5-10 ) and fine (PM 2.5 ) size fractions. The samples collected during the period January 2005 to March 2006, were analyzed by anodic stripping voltammetry (ASV) and inductively coupled plasma atomic emission spectrometry (ICP-AES) to determine the fine and coarse particulate concentrations of the heavy metals Zn, Pb, Cd, Cu, Fe, Mn and Ni. Concerning the elements Pb, Cd and Ni regulated by the European Union, annual average concentrations were lower than the prospective assessment thresholds, while concentration levels of Mn were in compliance with the values proposed by the World Health Organization. The concentrations of PM 10 particulates were about two times as that of the PM 2.5 particulates. Additionally, the ratio of fine (PM 2.5 ) to coarse (PM 2.5-10 ) particle concentrations was 0.44, indicating enrichment in the coarse particulates. Fe and Zn concentrations were mostly in the coarse particulate mode. Furthermore, the Pb/Cd average ratio in coarse and fine airborne particulates suggests that Pb is emitted by car exhausts and mainly industrial sources. Moreover, correlation analysis between airborne particulate matter (PM) and toxic elements was carried out to investigate the sources that affect the presence of these elements in coarse and fine particulates.

Seasonal Variation of Atmospheric Composition of Water-Soluble Inorganic Species at Rural Background Site in Tanzania, East Africa

Samples of coarse, fine and PM10 aerosols were collected at a rural Morogoro sites, during the 2005 dry season and 2006 wet season campaigns using a “Gent” PM10 stacked filter unit sampler with sequential Nuclepore polycarbonate filters. A total of 80 aerosol samples were analyzed for water-soluble inorganic ions components using Ion Chromatography. The mean concentration for the anions Cl-, NO3 -, and SO4 2- and the cations Na+, NH4 +, K+, Mg2+, Ca2+, showed seasonal variation in all size fractions with higher levels during the 2005 dry season campaign than the 2006 wet season campaign. The mean concentrations and associated standard deviation of fine, coarse and PM10 mass were, 17±4, 52±27 and 69±29 μg/m3 during the 2005 dry season campaign and 13±5, 34±23 and 47±25 μg/m3 for the 2006 wet season campaign, respectively. Ca2+ was the most important cation and the SO4 2- was the main acidifying anionic component in PM10 while NH4 + was the most abundant cation in the fine fraction and Cl- the main anionic species in the coarse fraction. The ion balance ratios were all larger than 1.0; they range from 1.30 to 1.44 for the fine fraction and from 2.01 to 3.14 for the coarse fraction. The carbonates were not measured by Ion Chromatography therefore; these missing carbonates are thought to be largely responsible for the observed deviation from 1.0. The study suggests that primary sources such as soil dust dispersion and biomass burning made a significant contribution to the atmospheric particulate pollution in Morogoro. Keywords : Ion chromatography; Aerosol Characterization; coarse, fine and PM10 fractions; Meteorology

Elemental Composition and Sources of Atmospheric Particulate Matter in Dar es Salaam, Tanzania

An intensive aerosol field campaign was carried out from 16 August to 16 September 2005 (dry season) at a kerbside in Dar es Salaam, Tanzania. A Gent PM10 stacked filter unit sampler with coarse and fine Nuclepore polycarbonate filters, providing fine (0.4 μm) and coarse (8 μm) size fractions, was deployed. A total of 64 parallel collections were made. All samples were analysed for the PM mass by weighing. A further analysis was performed for 25 elements by particle-induced x-ray emission spectrometry. The PM10 mass, as derived from the stacked filter unit samples, was, on average, 58 μg/m3. The concentrations of the heavy metals were lower than those for the elements of crustal origin. Nevertheless, some typical anthropogenic metals, such as Zn and Pb, exhibited much higher median PM10 levels, suggesting strong local sources for these elements in Dar es Salaam. The results also showed very strong day/night differences for the crustal elements (Al, Si, Ca, Ti and Fe). Most elements exhibit strong correlations in the coarse size fraction and somewhat weaker ones in the fine size fraction suggesting that they may originate predominantly from the same source. Principal component analysis with VARIMAX rotation was applied to the data set. Five and four components were identified for the fine and coarse fractions and explained 86.5% and 90.8% of the variance in the data set respectively. Keywords: PIXE; Atmospheric Aerosols; Elements; Size Fractions; PCA; Kerbside

Seasonal variation of water-soluble inorganic species in the coarse and fine atmospheric aerosols at Dar es Salaam, Tanzania

The ionic composition of coarse, fine and total PM10 was investigated in aerosol samples collected from a kerbside in Dar es Salaam during the 2005 dry season and 2006 wet season. A “Gent” PM10 stacked filter unit sampler with sequential Nuclepore polycarbonate filters, providing coarse (8 μm) and fine (0.4 μm) size fractions, was deployed. The mean concentrations and associated standard deviation of fine, coarse and PM10 were, respectively, 17 ± 4, 52 ± 27, and 69 ± 29 μg/m 3 during the 2005 dry season campaign and 13 ± 5, 34 ± 23 and 47 ± 25 μg/m 3 for the 2006 wet season campaign. The higher PM mass concentrations during the dry season campaign are essentially due to soil dust dispersal, much biomass burning and temperature inversions. Chloride, Na + and Mg 2+ were the dominant ions in coarse fraction, indicating a significant influence of sea-salt aerosols. In the fine fraction, SO 4 2 - and NH 4 + and K + were the most important ions. The mean equivalent PM2 NO 3 - concentration in the 2005 dry season campaign was two times higher than in the 2006 wet season campaign, probably due to reaction of NaCl (sea-salt) with HNO 3 as a result of higher levels of NO x during the dry season and/or reduced volatilization of NH 4NO 3 due to lower temperature in the dry season. The results from our water-soluble ions study strongly suggests that biomass burning and secondary aerosols make a significant contribution to fine particulate mass in Dar es Salaam atmosphere. Thus, burning of waste and biomass are thought to be the major causes for the atmospheric particulate pollution in Dar es Salaam during the dry season.

Chemical composition and mass closure for PM10 aerosols during the 2005 dry season at a rural site in Morogoro, Tanzania

AbstractAn intensive aerosol field campaign was carried out from 11 July to 11 August 2005 (dry season) at a rural site in Morogoro, Tanzania. The objectives were to determine the chemical composition of the atmospheric particulate matter (PM) and to examine to which extent the gravimetric PM mass can be explained by the measured aerosol components. Two low‐volume filter samplers were deployed, a PM10 filter holder with two Whatman QM‐A quartz fibre filters in series and a Gent PM10 stacked filter unit (SFU) sampler with coarse and fine Nuclepore polycarbonate filters. The samplers operated in parallel and a total of 51 parallel collections were made. All samples were analysed for the PM mass by weighing. Depending on the sampler type and/or collection substrate, further analyses were performed for 25 elements by particle‐induced x‐ray emission spectrometry, for major water‐soluble inorganic ions by ion chromatography, and for organic carbon and elemental carbon by a thermal—optical transmission technique. The PM10 mass, as derived from the SFU samples, was, on an average, 46 ± 12 µg/m3. Aerosol chemical mass closure calculations were made for this PM10 mass; eight aerosol components were considered and they explained 93% of the average PM10 mass. Organic matter (OM) and crustal matter were the dominant aerosol components; they accounted for, on an average, 44% and 33%, respectively, of the PM10 aerosol. The large contribution from OM is thought to originate mainly from the burning of biomass, especially of charcoal and agricultural residues. Copyright © 2009 John Wiley &amp; Sons, Ltd.